Biology Reference
In-Depth Information
A couple of decades before the term “electronic nose” came into being, army researchers,
much like those at Southwest Research Institute, started thinking about replacing the dog, a
sometimes unwieldy biological system, with a better system.
The experience of using sentry dogs in Vietnam in the early 1960s made for some imagin-
ative leaps of faith, and while some army researchers, like Nick Montanarelli, stuck with the
tried and true and played around the edges by trying different breeds of dogs for scent detec-
tion, other researchers at the U.S. Army Limited War Laboratory went further. Dogs' noses
were great for detecting the enemy, and dogs' barks were great for arousing sleeping soldiers.
What about partly mechanizing and miniaturizing that system?
So in 1965, army researchers started playing with “insect ambush detectors,” a reasonable
riff on the reality that blood-loving insects were ideal candidates for the “bio” part of the
machine: ticks, mosquitoes, bed bugs, giant conenose bugs. All those insects use the warm
breath of vertebrates to find their next meal. Researchers rigged up a plastic tube with a bel-
lows, a microphone, and a sanded piano wire that would twang when the bugs' feet started a
frenetic dance because they sensed a nearby meal. Ta. Da. An “ambush detector,” ready for a
wild rumpus when it smelled the breath of enemy soldiers.
Early work narrowed down the best bugs for the job. When fleas sensed humans, they
started jumping violently. They wouldn't settle down. They had to be fed too often. Bed bugs,
like fleas, got overly excited about the prospect of a hearty meal. Ticks were an early possibil-
ity. They loved the smell of human breath and could move quickly, though they didn't jump.
I've watched them crawling up my arm, so I know. They have soft feet. That's why you think
you can feel something crawling on you, but it's just a vague sense, and you forget about it.
The next time you think about the tick is when someone tells you one is attached to the back
of your neck. This is advantageous for ticks but not for army researchers, even with a micro-
phone inside the detector. The researchers tried tying weights to their tiny tick feet, but they
still were too silent, even wearing clodhoppers.
Conenose bugs—commonly known as kissing bugs because they most love the fleshy part
of your face or lips for their bloodsucking—were just right. Until the researchers tested them.
The bug machine performed miserably in the 1966 Panama Canal field test, the army report
noted. The false positives were through the roof. Once the conenose bugs got amped up, they
were as bad as the bed bugs: They refused to settle down. Their feet just kept noisily send-
ing out signals. Food! Food! Researchers realized it wasn't just food. Motion excited the bugs.
Wind excited them. Pretty much everything excited them. It was like a kids' sleepover.
In what would become a template excuse for not finding something as good as the dog's
nose, the final report said that using blood-loving bugs as ambush detectors remained “tech-
nically feasible.” That term is a big ol' hairy clue to recognize a failed experiment.
